/**
  ******************************************************************************
  * @file    system_py32f0xx.c
  * @author  MCU SYSTEM Team
  * @Version V1.0.0
  * @Date    2020-10-19
  * @brief   CMSIS Cortex-M0+ Device Peripheral Access Layer System Source File.
  ******************************************************************************
  */

#include "py32f0xx.h"

#if !defined  (HSE_VALUE) 
#define HSE_VALUE    8000000U    /*!< Value of the External oscillator in Hz */
#endif /* HSE_VALUE */

#if !defined  (HSI_VALUE)
  #define HSI_VALUE  8000000U   /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */

#if !defined  (LSI_VALUE) 
 #define LSI_VALUE   32000U      /*!< Value of LSI in Hz*/
#endif /* LSI_VALUE */ 

#if !defined  (LSE_VALUE)
  #define LSE_VALUE  32768U      /*!< Value of LSE in Hz*/
#endif /* LSE_VALUE */


/************************* Miscellaneous Configuration ************************/
/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define FORBID_VECT_TAB_MIGRATION */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET  0x00 /*!< Vector Table base offset field.
                                   This value must be a multiple of 0x100. */
/******************************************************************************/
/*----------------------------------------------------------------------------
  Clock Variable definitions
 *----------------------------------------------------------------------------*/
  /* This variable is updated in three ways:
      1) by calling CMSIS function SystemCoreClockUpdate()
      2) by calling HAL API function HAL_RCC_GetHCLKFreq()
      3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
         Note: If you use this function to configure the system clock; then there
               is no need to call the 2 first functions listed above, since SystemCoreClock
               variable is updated automatically.
  */
  uint32_t SystemCoreClock = HSI_VALUE;

  const uint32_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
  const uint32_t APBPrescTable[8] =  {0, 0, 0, 0, 1, 2, 3, 4}; 

/*----------------------------------------------------------------------------
  Clock functions
 *----------------------------------------------------------------------------*/
void SystemCoreClockUpdate (void)            /* Get Core Clock Frequency      */
{ 
  const uint32_t hsiFreqTable[8] = {4000000,8000000,16000000,22120000,24000000,4000000,4000000,4000000};
  uint32_t tmp;
  uint32_t hsidiv;
  uint32_t hsifs;

    /* Get SYSCLK source -------------------------------------------------------*/
  switch (RCC->CFGR & RCC_CFGR_SWS)
  {
    case RCC_CFGR_SWS_0:  /* HSE used as system clock */
      SystemCoreClock = HSE_VALUE;
      break;

    case (RCC_CFGR_SWS_1 | RCC_CFGR_SWS_0):  /* LSI used as system clock */
      SystemCoreClock = LSI_VALUE;
      break;

    case RCC_CFGR_SWS_2:  /* LSE used as system clock */
      SystemCoreClock = LSE_VALUE;
      break;

    case RCC_CFGR_SWS_1:  /* PLL used as system clock */
      if((RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC) == RCC_PLLCFGR_PLLSRC_HSI) /* HSI used as PLL clock source */
      {
        hsifs = ((READ_BIT(RCC->ICSCR, RCC_ICSCR_HSI_FS)) >> RCC_ICSCR_HSI_FS_Pos);
        SystemCoreClock = 2 * hsiFreqTable[hsifs%8];
      }else  /* HSE used as PLL clock source */
      {
        SystemCoreClock = 2 * HSE_VALUE;
      }
      break;
      
    case 0x00000000U:  /* HSI used as system clock */
    default:                /* HSI used as system clock */
      hsifs = ((READ_BIT(RCC->ICSCR, RCC_ICSCR_HSI_FS)) >> RCC_ICSCR_HSI_FS_Pos);
      hsidiv = (1UL << ((READ_BIT(RCC->CR, RCC_CR_HSIDIV))>> RCC_CR_HSIDIV_Pos));
      SystemCoreClock = (hsiFreqTable[hsifs%8]/hsidiv);
      break;
  }
  /* Compute HCLK clock frequency --------------------------------------------*/
  /* Get HCLK prescaler */
  tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> RCC_CFGR_HPRE_Pos)];
  /* HCLK clock frequency */
  SystemCoreClock >>= tmp;
}

/**
 * Initialize the system
 *
 * @param  none
 * @return none
 *
 * @brief  Setup the microcontroller system.
 *         Initialize the System.
 */
void SystemInit (void)
{
    //配置HSI默认时钟为8MHz
    RCC->ICSCR = (RCC->ICSCR & 0xFFFF0000) | (0x1<<13) | *(uint32_t *)(0x1fff0f04); 
    
    /* Configure the Vector Table location add offset address ------------------*/
#ifdef VECT_TAB_SRAM
    SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
#else
    SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
#endif
}

#ifndef FORBID_VECT_TAB_MIGRATION
#ifndef VECT_TAB_SRAM
#if (defined (__CC_ARM)) || (defined (__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050))
extern int32_t $Super$$main(void);
uint32_t VECT_SRAM_TAB[48]__attribute__((section(".ARM.__at_0x20000000")));

/* re-define main function */
int $Sub$$main(void)
{
    uint8_t i;
    uint32_t *pFmcVect = (uint32_t *)(FLASH_BASE | VECT_TAB_OFFSET);
    for(i=0; i<48; i++)
    {
        VECT_SRAM_TAB[i] = pFmcVect[i];
    }

    SCB->VTOR = SRAM_BASE;
    
    $Super$$main();
    return 0;
}
#elif defined(__ICCARM__)
extern int32_t main(void);
/* __low_level_init will auto called by IAR cstartup */
extern void __iar_data_init3(void);
uint32_t VECT_SRAM_TAB[48] @SRAM_BASE;
int __low_level_init(void)
{
    uint8_t i;
    uint32_t *pFmcVect = (uint32_t *)(FLASH_BASE | VECT_TAB_OFFSET);
    // call IAR table copy function.
    __iar_data_init3();

    for(i=0; i<48; i++)
    {
        VECT_SRAM_TAB[i] = pFmcVect[i];
    }

    SCB->VTOR = SRAM_BASE;

    main();
    return 0;
}
#endif
#endif
#endif
